Removable compartments for workpiece stocker

ABSTRACT

The present invention discloses apparatuses and method for configuring a compartmentable equipment to accommodate emergency responses. An exemplary equipment comprises a plurality of removable compartments for storing workpieces so that in emergency events, such as power failure or equipment failure, the workpieces can be removed from the equipment for continuing processing without disrupting the flow of the fabrication facility. The compartmentable equipment can comprise emergency access ports, including mating interface to a portable workpiece removal equipment to allow accessing the individual compartments without compromising the quality, defects and yield of the workpieces stored in the stocker.

This application claims priority from U.S. provisional patentapplication Ser. No. 60/859,201, filed on Nov. 15, 2006, entitled“Removable compartments for workpiece stocker”; which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to semiconductor equipment, and moreparticularly, to equipment and method to improve fabrication facilityprocessing.

BACKGROUND

Stockers generally are installed within a semiconductor facility fortemporarily storing workpieces, such as wafers, flat panel displays,LCD, photolithography reticles, or masks. In the process ofmanufacturing semiconductor devices, LCD panels, and others, there arehundreds of processing equipments and thus hundreds of manufacturingsteps. It is very difficult for the flow of the wafers, flat panels, orLCDs (hereafter workpiece) to be uniform from step to step, from tool totool. Despite the best planners, there is always the unexpectedscenario, such as a tool down, an emergency lot coming through, aperiodic maintenance lasting longer than planned, thus there are variousaccumulations of the workpieces at certain steps for certain tools. Theaccumulated workpieces will need to be stored in a storage stocker,waiting to be processed.

Further, photolithography process is a critical process in thesemiconductor fabrication facility, involving a large number ofphotolithography masks or reticles (hereinafter reticle). The reticlesthus are typically stored in a storage stocker, and being retrieved whenneeded into the lithography exposure equipment.

The storage of workpieces and reticles (hereafter articles) is much morecomplicated due to the requirement of cleanliness. Damages to thearticles can be physical damages in the form of particles, or chemicaldamages, in the form of interactions. With the critical dimension of thesemiconductor device processing surpassing 0.1 micron, particles of 0.1micron sizes, and reactive species will need to be prevented fromapproaching the articles. The storage areas typically would need to beeven cleaner than the processing facility, to ensure less cleaningbetween processing.

Thus the stocker storage areas is typically designed to be sealed offfrom the outside environment, preferably with constant purging, and evenwith inert gas flow to prevent possible chemical reactions. Access tothe storage areas is load-locked, to ensure isolation between the cleanstorage environment and the outside environment.

This creates a potential problem in the event of the failure of thestocker, such as a transport malfunction, or a load lock malfunction,the stocker storage becomes isolated, with no way to retrieve articlesfrom the stocker storage. This failure, through the chain reaction,could shut down a large portion of the fabrication facility.

SUMMARY

The present invention discloses apparatuses and method for configuring acompartmentable equipment to accommodate emergency responses. Anexemplary equipment comprises a plurality of removable compartments forstoring workpieces so that in emergency events, such as power failure orequipment failure, the workpieces can be removed from the equipment forcontinuing processing without disrupting the flow of the fabricationfacility.

In an embodiment, the compartmentable equipment is configured for astocker for storing semiconductor workpieces such as reticles or wafers.A stocker according to an embodiment of the present invention provides aplurality of removable compartments where the workpieces are stored.Thus in the events of failure, the workpieces can be accessed byremoving the appropriate compartments. The compartments are preferablydesigned for removal without compromising the quality of otherworkpieces.

In an embodiment, the compartments are open and removable. An exemplarystocker comprises a plurality of open and removable compartmentsarranged in a shelving configuration, accessible by a robot handlingsystem. The compartments may be arranged in a circular configurationsurrounding a radial and rotational robot, or the compartments may bearranged in a linear xy configuration, facing a linear xy robot. Opencompartments allow the ease of operations such as picking up or placingworkpieces in and out of the stocker without the need for opening thedoors of the compartments. The storage of workpieces in compartmentsallows the quick removal of the individual compartments during equipmentfailure. The workpieces can also be stored in a container within thecompartments.

In an embodiment, the compartments are sealed, preferably individuallysealed. Sealed compartments allow the emergency removal withoutcontaminating the remaining workpieces due to the emergency access.Sealed compartments further prevent the cross contamination betweencompartments, since the compartments are sealed against each other.

In an embodiment, the compartments are open during operations, thusproviding improve throughput and ease of accessing the workpieces. Inone aspect, the compartments can be sealed when the workpieces are notbeing accessed. A sealed compartment can be open when needed foraccessing the workpieces stored within. Or a controller can keep trackof the needed workpieces, and thus can open the sealed compartments justbefore the compartments need to be opened. In another aspect, thecompartments can be sealed during emergency accessing operation. Thecompartments are opened normally, but are sealed when a failurecondition is detected. The compartments can be sealed by automaticallyor manually sealing the compartments before accessing the emergencyoperation. In an aspect, the system comprises automatic or manualsealing mechanism for isolating the individual compartments.

In an embodiment, the compartmentable equipment comprises emergencyaccess ports to remove the compartments. The emergency access ports canbe positioned at a side of the equipment, either in the front sidefacing the clean room, or in the back sides facing the equipment chasearea. The emergency access ports allow an operator to gain access to theindividual compartments to remove them in the events of failure,preferably without compromising the quality, e.g. cleanliness orexposing to contaminants, of other workpieces or other compartments.

In an embodiment, the emergency access ports include mating interface toa portable workpiece removal equipment. During emergency situations, theworkpiece removal equipment links to the mating interface of the stockerto allow accessing the individual compartments without compromising thequality, defects and yield of the workpieces stored in the stocker. Theworkpiece removal equipment can include a portable clean room area, thusallowing forming an integrated clean room extension to the stocker forthe transfer of the compartments. In one aspect, the workpiece removalequipment includes a robot handling assembly for accessing thecompartments. In other aspect, the workpiece removal equipment includesa loadlock interface for allowing an operator to enter the stocker toremove the compartment. The workpiece removal equipment can also includecontainer boxes for storing the compartments to remove the workpiecesout of the clean environment.

The stocker system can include rotatable carousel for accessing all thecompartments. The system can also include opening or moving mechanismfor accessing inner compartments.

In an embodiment, the system comprises emergency removal equipment tofacilitate the removal of the compartments. A compartment can storehundred or so workpieces, thus can be heavy. Further, for smallfootprint, the compartments might be stacked several shelves high, andthus it is difficult for human access.

In an embodiment, the system comprises air flow configuration formaintaining cleanliness for the compartments. The air flow can cover thecommon area as well as the inside of the compartment.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 shows an exemplary embodiment of the stocker according to thepresent invention.

FIG. 2 shows an exemplary stocker with opened door for the manualwithdrawal of a container.

FIG. 3 shows a cross section of a container for a stocker (line III-IIIin FIG. 4).

FIG. 4 shows another view of a container.

FIG. 5 shows a top view of a robot handling assembly unit.

FIG. 6 shows a side view of a robot handling unit.

FIG. 7 shows another embodiment of the stocker according to the presentinvention, top view.

FIG. 8 shows another embodiment of the stocker according to the presentinvention, top view.

FIG. 9 shows a side view of an exemplary stocker with two robotpositions.

FIG. 10 shows a side view of an exemplary stocker with clean gas flowconfiguration.

FIG. 11 shows an exemplary computer system for the present invention.

FIG. 12 shows an exemplary computer environment for the presentinvention.

DETAIL DESCRIPTIONS

During the processing of semiconductor workpieces in the manufacture ofmicroelectronics, different equipments are employed for several hundredprocessing steps. The process flow of a workpiece is essential serial,with most of the tools operate on the workpieces one at a time. Thefailure of any link in the fabrication process would severely disruptthe process flow, resulting in loss of manufacturing productivity. Thepresent invention relates to an apparatus and method for improvingreliability with moving equipment, involving emergency accesses for thestored workpieces in an equipment to ensure continuous flow ofworkpieces for a fabrication facility.

In an exemplary embodiment, the present invention provides the handlingor movement of workpieces in a manner which assured a continuous flow ofworkpieces within an equipment and within a fabrication facility, evenin the event of part failures. The present invention discloses anemergency mechanism for prevent equipment failure from affecting theprocess flow. In one aspect, the present invention discloses amanagement methodology and apparatuses to a fabrication equipment sothat in the event of the failure of that particular fabricationequipment, it still can support the operation of the fabricationfacility while waiting for repair.

The present invention thus provides, in an exemplary embodiment,apparatuses and method for configuring a compartmentable equipment toaccommodate emergency responses. An exemplary equipment comprises aplurality of removable compartments for storing workpieces so that inemergency events, such as power failure or equipment failure, theworkpieces can be removed from the equipment for continuing processingwithout disrupting the flow of the fabrication facility.

In an embodiment, the compartmentable equipment is configured for astocker for storing semiconductor workpieces such as reticles or wafers.A stocker is usually designed for temporary storing the workpieces, thusthe flow of the fabrication facility would be severely affected if thestocker is temporary out of service, preventing access of the neededworkpieces. A stocker according to an embodiment of the presentinvention provides a plurality of removable compartments where theworkpieces are stored. Thus in the events of failure, the workpieces canbe accessed by removing the appropriate compartments. The compartmentsare preferably designed for removal without compromising the quality ofother workpieces.

In an embodiment, the compartments are open and removable. An exemplarystocker comprises a plurality of open and removable compartmentsarranged in a shelving configuration, accessible by a robot handlingsystem. The compartments may be arranged in a circular configurationsurrounding a radial and rotational robot, or the compartments may bearranged in a linear xy configuration, facing a linear xy robot. In thisconfiguration, the robot handler can be designed with three degrees offreedom, e.g. radial, rotational and vertical movements, thus can haveimproved speed and throughput. Three degree of freedom robots are wellestablished with minimum particle generation, thus this configurationcan provide cleanliness for workpiece storage. In addition, the stockerstorage area is stationary with the movable components are the robotassembly, thus further contributing to the cleanliness of the storagestocker.

In an embodiment, the stocker configuration provides an open storagearea with the workpieces stored bare for easy access. The storing ofbare workpieces provides fast access, space saving and ease of clean airpurging. The storage area can be configured with a plurality of opencompartments, arranging surrounding a robot handling assembly, also inthe vertical direction. Open compartments allow the ease of operationssuch as picking up or placing workpieces in and out of the stockerwithout the need for opening the doors of the compartments. The storageof workpieces in compartments allows the quick removal of the individualcompartments during equipment failure. The workpieces can also be storedin a plurality of containers within the compartments.

In an embodiment, the stocker configuration provides the storage of theworkpieces in a highly dense configuration, in either vertical orhorizontal positions. The stocker provides a circumferential edgegripper robot handling assembly, approaching and picking up theworkpieces from the circumferential edges, thus allowing the denseworkpiece storage configuration.

The stocker according to an exemplary embodiment of the presentinvention is designed for storing contamination-sensitive articles suchas semiconductor wafers, and reticles. The stocker designed isparticularly configured for space-saving storage and flexible handling.The stocker, in particular, is well suitable for storing a large numberof 300 mm or larger wafer on a small storage space under cleanconditions.

The open storage can be partitioned into carrier racks or shelves toreduce the risk of cross contamination. The compartments can beremovably fastened to carrier racks or shelves, and can include storagecontainers. The stationary of the carrier racks, the storage containers,the compartments and the articles prevent particles generated frommotions, thus substantially reducing the risk of particles generated byabrasion, movement and cross contamination air flow.

The storage compartments and the storage containers are preferablyshaped as an open, box-like container, where the robot handling unit canbe adapted optimally to inserting and taking articles out of the storagecompartments or containers. In a preferred embodiment, the compartmentsor containers are designed for highly dense storage of articles, forexample semiconductor wafer with a pitch distance of less than 5 mm,preferably about 2.5 mm or less. The storage compartments or containersare arranged in a shelving configuration surrounding the robot handlingunit, and preferably approximately circular. The storage compartments orcontainers can also be arranged in a x-y array, with the shelvesopenings facing a robotic mechanism for transferring the articles. Thestationary stocker comprises a plurality of vertically and horizontallyspaced shelves each for storing a plurality of articles. The shelves canalso designed for storing a plurality of compartments or containerswhere the articles are stored within.

This configuration can provide space-saving arrangement and at the sametime high storage capacity. In addition a very fast accessing of storedarticles can be possible in this configuration. The particularlypreferred configuration of circular arrangement of the storagecontainers is well suited with a three degree of freedom robot such as aSCARA robot. The robots includes articulated arms, mobile in ahorizontal plane with rotational and radially to a center point. Therobot can also be a six axis robot.

Robot assemblies are an important component in automation, especially inmanufacturing facilities and manufacturing equipments. For example, inthe semiconductor industry, robot arms are used to handle semiconductorwafers, flat panel display, LCD, reticles, masks, or carrier boxes.

In the semiconductor fabrication facility, robot can be used totransport workpieces, typically stored in carrier boxes, from onelocation to another location, from one equipment to another equipment.In a process system, a robot is typically used to remove the workpiecesfrom the carrier boxes, and then loaded into a loadlock. Another robotcan be used to move the workpiece from the loadlock into a processingchamber, and from one processing chamber to another processing chamber.Thus within a processing system, there might be a plurality of robots,each one is designed for a particular task. The processing system couldbe a deposition system, an etch system, a lithography system, ametrology system, an inspection system, an implantation system, atreatment system, or any workpiece processing system.

Generally speaking, robot handling assembly is different for vacuumsystem and atmospheric system. The stocker, designed for storing theworkpieces until needed, is typically an atmospheric system where arobot is typically used to remove the workpieces from the carrier boxes,and then loaded into a loadlock. Another robot can be used to move theworkpiece from the loadlock into a storage chamber, where the workpiecesare stored without the original carrier boxes. For box stocker system,the workpieces are stored together with the carrier boxes, without theneed for removing them out of the carrier boxes.

The robot mechanism can comprises articulate arm joints to move anarticle or a container into and out of the stationary stocker. Further,the robot arm assembly comprises a flexible multiple-link mechanism,designed to reach the shelves of the stocker. The arm assembly can haveindependent radial and rotational movements to reach the arranged spacesof the stocker.

The stocker of the present invention can provide storage compartments orcontainers forming approximately a substantially circular cabinet arounda robot handling device. The robot assembly is preferably stationary,with articulate arm joints reaching the inner side of the stationarystocker to transfer articles.

The robot handling unit includes vertical movement to access thevertical storage compartments or containers. The stocker can alsoinclude a second handling unit for transferring the articles into orfrom the compartments or containers. The stocker can include backsidedoors for accessing the back of the article containers. The back doorsallow access to the articles in emergency events, such as a systemcrash. The stocker can include a blower for producing a continuous cleangas flow toward the containers, and preferably blowing contaminationefficiently downward.

In one embodiment, the present invention discloses an emergency systemfor emergency retrieval of stored workpieces. The emergency systemcomprises an emergency access to allow the retrieval of the articleseven when there is a general failure. The emergency access can be anemergency door, preferably at the front side, or an equipment accessthat is not normally use such as an access used by a robot handling inthe normal operation. The emergency access can be handled by anoperator, or by an external handling equipment. The external handlingequipment is preferably independent to be able to operate even with ageneral failure.

The emergency system is generally designed for robotic access, thus canbe very compact with minimum spare volume. The emergency system can alsobe designed for operator access, comprising an interface for a load lockentrance.

The emergency system is designed for emergency transfer to processequipment, thus should be designed with contamination concernsaccordingly. Thus in general, the emergency system is treated like an IOloader with respect to the issue of transportation. For example, thearticles stored in the output buffer is preferably stored in the formthat can be handled or transported in a clean room environment, as inthe case of the articles stored in the IO loaders. Thus the articles arepreferably stored in carrier boxes, so that there is no contamination ordamage to the articles during the transfer to the needed tools. Thecarrier boxes can be designed for operator handling, or for OHThandling.

The storage system, such as workpiece or reticle stocker, generallycomprises a storage area with an IO loader section, communicated by arobotic handling system. The storage area is preferably cleaner than theoutside environment, and therefore the storage system preferablycomprises a load lock linking the storage area to the IO loader. Thestorage area can store the articles in their bare form (e.g. only thearticle is stored), in their transfer form (e.g. inside carrier boxes),or in their storage form. The storage form is typically between bare andtransfer forms, providing better coverage and protection than the bareform, but not as much as the transfer form.

The storage form also can provide emergency protection to the articlesin the storage area, in the event of the environmental breach. In thefailure of e.g. clean air flow, the articles stored in bare form in thestorage area can be all contaminated. A storage form can prevent thecontamination. The storage form can be much simpler than a transferform, since the storage form is not designed for transportation. Thusstorage in storage form is much more cost effective than storage intransfer form.

An exemplary stocker 10 is shown in FIG. 1. The stocker 10 includes ahousing 12, containing a robot handling unit 14 and a carrier rack 16 tosupport a plurality of article compartments (or containers) 18. Thehousing 12 surrounds the robot handling unit 14, the carrier rack 16 andthe compartments 18 to form complete enclosure for a clean environment.The top of the housing can be provided with blower and filters (notshown) to produce within the housing 12 a flow of clean air from the topto the bottom. Each compartments 18 is designed to store a plurality ofcontamination-sensitive articles. In a preferred embodiment, thearticles are semiconductor wafers, which can be stored vertically in thecompartments 18. In an exemplary embodiment, each compartments can hold100 wafers of 300 mm. The distance between the stored wafers can be alittle as 2.5 mm. The robot handling unit 14 can be a radial, rotationaland vertical robot, or can be a 6-axis robot, located in a corner of thehousing 12. The carrier rack 16 with the compartments 18 is forming aC-shape surrounding the robot handling unit 14. The stocker 10 canfurther comprise a pre-aligner 28 for aligning a wafer 20. The wafer 20can be taken in and out of the pre-aligner 28 by a door 30, connected toa FOUP 32.

The exemplary stocker 10 comprises an emergency access port 22 foraccessing the compartments (or containers) 18. The emergency access port22 is positioned at the backside of the stocker 10, and provides aninterface to the clean environment of the stocker. The interface can bemated to a portable workpiece removal environment 11, which can act as aloadlock to allow the transfer of individual compartments or containers18 out of the stocker without compromising the quality of the remainingworkpieces.

The emergency access port 22 can include a mating interface so that anenclosure 11 can link to the stocker 10, providing a clean interfacebetween the stocker and the outside environment. During emergencysituation, a portable mini-environment can link to the stocker throughthe interface of the emergency access port 22 to allow accessing theworkpieces or compartments in the stocker, or to put the workpieces orcompartments into another suitable container 18′ for bringing out of thestocker.

In one aspect, the portable enclosure 11 provides a load lock to theinside of the stocker, equipped with clean room air purging orexhausting. An operator can enter the portable enclosure 11, and becomesclean through a few purging and exhausting cycles of the enclosure 11before opening the emergency access port 22. The enclosure 11 nowbecomes a clean room extension to the stocker, allowing the operator toaccess the individual workpieces in the stocker without contaminate theremaining workpieces. The operator can carry tools and carrier boxes toaccess the workpieces and the compartments. The workpieces or thecompartments can be removed from the stocker and put into a clean roomcarrier box to be carried out of the stocker and the enclosure. With thecompartments 18 storing a plurality of workpieces (e.g. 50 to 100),removing and storing the compartments in a carrier box is much quickerthan accessing individual workpieces. The carrier boxes are sealed, thuscan be taken out of the stocker to the outside environment, and returnedto the facility for processing. Other equipment can be utilized fortransfer the workpieces from the carrier boxes to the destination in aclean environment.

In other aspect, the operator remains outside the portable enclosure andoperates suitable equipment in the enclosure to collect the workpiecesand the compartments, together with putting them into suitable carrierboxes. The equipment can be a robot handling assembly or a glove box. Toaccess the vertical dimension, vertical lift can be incorporated, eitherinside or outside of the enclosure.

Thus an open compartments stocker according to an embodiment of thepresent invention comprises an emergency access port and/or a matinginterface with a portable clean environment for emergency access theworkpieces. Storing the workpieces within open compartments allows fastaccess, and the emergency access allows access to the workpieces or thecompartments during equipment failures.

FIGS. 3 and 4 show an exemplary embodiment of a compartment 18, whichincludes a rear wall 38, a bottom wall 40 and two side panels 42, 44.The rear wall 38 and the bottom wall 40 preferably provide an openingfor releasing clean air flow diagonally across the wafer 20. The airflow 48 between the individual wafers 20 passes through and ensures thatany existing particles and foreign matter are removed diagonallydownward from the container 18.

Within the compartment 18, four comb like-components with splits 50, 52,54, 56 are arranged. The split 50-56 are arranged to hold a wafer by itsdown and back side to permit the removal of the wafer with the robothandling unit 14.

At the upper corner area, there exists a recess 58 to insert a retainer60. The retainer 60 is designed to hold the wafers in place duringmovement of the container 18. Each compartment 18 may have a handle (notshown), which is connected with the retainer 60, so that a withdrawal ofthe container 18 is only possible if the retainer 60 is inserted in therecess 58.

FIGS. 5 and 6 show an exemplary robot handling unit according to thepresent invention. The integrated grip arm 14 possesses a first gripperarm 24 and a second gripper arm 26. The first gripper arm 24 is designedas a grip arm, where a wafer 20 a can be seized at the edges in avertical position. The grip arm 24 surrounds the wafer 20 a at its outercircumference in an exemplary C-shaped. Two grip elements 64 and 66 arearranged at the free ends of the grip arm 24. The grip arm 24 surroundsthe wafer 20 a along a circular arc “alpha” of more than 180°. The gripelements 64, 66 can hold the wafer 20 a therefore without firm wedgingand essentially alone due to gravity. For the pick up and placement of awafer 20 a in a carrier box 18, the grip elements 64, 66 can be opened.In this figure, only the grip element 66 is mobile.

The second gripper arm 26 comprises a Y-shape arm with grip elements 68,70 at the ends. The gripper arm 26 is holding a wafer in different plane72 than the gripper arm 24. A wafer 20 b is held by the grip elements68, 70 in the plane 72. The gripper arm 26 has a free end, thus canenter a FOUP to pick up or placing a wafer.

The grippers 24 and 26 are arranged at the free ends of an L-shaped armsegment 74 of an integrated grip arm 14. The arm segment 74 can beswiveling around an axle 76, which lies coaxially to a leg of the armsegment 74, where the gripper 24 is located. This arrangement makes itpossible to take and by a 90° rotation around the axle 76, bringing awafer 20 a into a horizontal position out of a vertical position fromthe carrier box 18. The integrated grip arm can then transfer the waferto a horizontal station. The integrated grip arm then switches gripper,and the gripper 26 can pick up the wafer and transfer to a FOUP. Wafersfrom the FOUP can be brought into the carrier box 18 by reverseoperations. The integrated grip arm thus can provide movement of thewafers from a FOUP to the storage area with the grippers 24 and 26.

The stocker 10 can provide random access to the stored wafer, thus caneliminate the need for a sorter. In particular, the robot handling unit14 is capable of selecting wafers 20 from arbitrary containers 18 into aFOUP 32. The stocker 10 thus can be integrated with a FOUP front endloader. Due to the vertical storage and the associated high densitystorage arrangement of the wafers, the stocker can achieve high storagecapacity with small footprint. The storage of the individual wafers inopen, separate, box shaped compartments ensures that cross contaminationbetween different wafers 20 is difficult despite the open storageconfiguration.

FIGS. 7 and 8 show exemplary embodiments of the present inventionstocker 80, comprising a plurality of compartments 81 surrounding arobot handling unit 82 in a circle. The handling unit 82 is depictedwith a SCARA robot with an articulate arm 84, that can move radially ina horizontal plane parallel to the view level. The articulate arm 84 isswiveling around a center point 86, which defines a circular arrangementof the containers 81. Thus the articulate arm 84 can provide movementswithin the horizontal plane, radially and rotationally to the centerpoint 86. The articulate arm 84 is arranged pick up and to placearticles 20 in radial direction in and out of containers 81.

FIG. 8 is a plan view on the exemplary stocker 80 along a cutting plane,e.g. the cutting plane VIII-VIII from corresponding FIG. 9. In thisplane, some containers 81 are missing from the circular arrangement. Inthese spaces, a second handling unit 92 and a Prealigner 94 can beprovided.

The robot handling unit 82 is designed to transfer a wafer from acompartment 81 to the Prealigner 94. In addition the robot handling unit82 can rotate the wafer, taking a vertical stored wafer in thecompartment 81 to a horizontal stored wafer position on the Prealigner94. The second handling unit 92 can be used to transfer the wafer fromthe Prealigner 94 to the FOUP 32. It is preferable that the load lockstation 96 possesses a hermetic connection to the housing 12, so thatthe wafer 20 can be transferred into the FOUP 32 contamination-free.

The second handling unit 92 can also be a robot with an articulate arm,radially movable to a center point to move the wafer between thePrealigner and the FOUPs. The load lock input/output station 96 caninclude two FOUP 32. This configuration can provide the functionality ofa sorter, providing the means to relocate and sort wafers 20 between twoFOUPs 32.

FIGS. 9 and 10 show an exemplary arrangement of the compartments 81 inthe vertical direction. The handling unit 82 can achieve the differentvertical levels of the compartments 81 by moving along two guide rails88 in vertical direction (perpendicular to the view level). Thecompartments 81 in this exemplary stocker include connections 90 forflowing cleaning gas. Connections 90 are arranged at the back of thecompartments 81, so that the cleaning gas flushes the compartments 81from the back to the front. In addition each connection 90 can includevalve 91 for selectively opened or closed. It is thus possible to flushthe compartments individually with cleaning gas.

FIG. 9 shows the compartments 81 arranged one above the other and in acircle around a handling unit 82. In FIG. 9, the wafers 20 are stored inhorizontal position in the compartments 102. With horizontal storage ofthe wafers, the handling unit 82 does not have to turn the wafers 20when taking in and out of the compartments. The robot handling unit 82is shown in two vertical positions, a top position numbered 82 and abottom position numbered 82′.

FIG. 9 also shows a blower and a filter unit 104 to provide a cleaninggas, preferably filtered clean air, to the interior of the housing 12.The blower and filter unit 104 receive ambient air, which is cleaned anddried and then flown afterwards into the interior of the housing. InFIG. 10, the cleaned air is flown over connections 90 at the back of theindividual compartments 102. The air flow and the cleaning gas thus flowfrom the back of the compartment 102, out to the opened front and thendownward 106. As discussed above, this flow provides a nozzle effect forthe vertical storage, thus strengthens the cleaning efficiency. A goodflow can also be achieved with the horizontal storage, as presented inthese figures. Alternatively, the flow can be from the inside outward.

The stocker is a stationary stocker, provided with a robot handler,movable in the vertical direction (upward and downward) and in therotational direction. The stocker is provided with a plural number ofshelves for storing articles and positioned inward, for transferringarticles between a loadlock station and the stationary stocker.

The robot assembly further comprises a plurality of sensors, such asworkpiece positioning sensors, image sensing of position errors, RFelectric field sensing, magnetic resonance sensing, laser scanning,sensing with photo detector arrays, motor operation sensing, armposition sensing, or any sensors related to the operation and service.Furthermore, the sensors provides the status and locations of the robotassembly, thus allowing the optimum utilization of the remainingoperative part of the assembly, plus the alerting the operator forservicing the inoperative parts of the assembly.

In an embodiment, the compartments are sealed, preferably individuallysealed. Sealed compartments allow the emergency removal withoutcontaminating the remaining workpieces due to the emergency access.Sealed compartments further prevent the cross contamination betweencompartments, since the compartments are sealed against each other. Withsealed compartments, in the events of failures, the stocker can beopened to remove the compartments. The sealed compartments arepreferably removable for ease of transport.

Sealed compartments might delay access during normal operation, sincethe compartment doors will need to be open and close for every workpieceaccess. Thus in an embodiment, the compartments are designed to beopened during normal operations, thus providing improved throughput andease of accessing the workpieces.

In one aspect, the compartments can be sealed when the workpieces arenot being accessed. A sealed compartment can be open when a workpiecereaches the compartment, or when a robot handler approaches thecompartment, either for storing or for picking a workpiece. For betterthroughput, a controller can keep track of the operations, the movementof the workpieces and the requirements of the compartments, and thus canopen the sealed compartments before the compartments need to be opened.The compartments can be open way ahead of time, or can be open just alittle before the needed time.

In another aspect, the compartments can be sealed during emergencyoperation. The compartments are opened under normal operatingconditions, and are close or sealed when a failure condition isdetected. Also, the compartments can be sealed before accessing theemergency removal of the compartment. The system can comprise automaticor manual sealing mechanism for isolating the individual compartments.The system then can initiate the sealing mechanism automatically whendetecting a failure condition. Or an operator can initiate a sealing orclosing of the compartments before accessing the stocker storage area.

The stocker system can include rotatable carousel for accessing all thecompartments. The system can also include opening or moving mechanismfor accessing inner compartments. The system can comprise emergencyremoval equipment to facilitate the removal of the compartments. Acompartment can store hundred or so workpieces, thus can be heavy.Further, for small footprint, the compartments might be stacked severalshelves high, and thus it is difficult for human access.

The present invention may also be embodied in a machine or computerreadable format, e.g., an appropriately programmed computer, a softwareprogram written in any of a variety of programming languages. Thesoftware program would be written to carry out various functionaloperations of the present invention. Moreover, a machine or computerreadable format of the present invention may be embodied in a variety ofprogram storage devices, such as a diskette, a hard disk, a CD, a DVD, anonvolatile electronic memory, or the like. The software program may berun on a variety of devices, e.g. a processor.

With reference to FIG. 13, an exemplary environment 300 for implementingvarious aspects of the invention includes a computer 301, comprising aprocessing unit 331, a system memory 332, and a system bus 330. Theprocessing unit 331 can be any of various available processors, such assingle microprocessor, dual microprocessors or other multiprocessorarchitectures. The system bus 330 can be any type of bus structures orarchitectures, such as 12-bit bus, Industrial Standard Architecture(ISA), Micro-Channel Architecture (MSA), Extended ISA (EISA),Intelligent Drive Electronics (IDE), VESA Local Bus (VLB), PeripheralComponent Interconnect (PCI), Universal Serial Bus (USB), AdvancedGraphics Port (AGP), Personal Computer Memory Card InternationalAssociation bus (PCMCIA), or Small Computer Systems Interface (SCST).

The system memory 332 can include volatile memory 333 and nonvolatilememory 334. Nonvolatile memory 334 can include read only memory (ROM),programmable ROM (PROM), electrically programmable ROM (EPROM),electrically erasable ROM (EEPROM), or flash memory. Volatile memory333, can include random access memory (RAM), synchronous RAM (SRAM),dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM(DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), or directRambus RAM (DRRAM).

Computer 301 also includes storage media 336, such asremovable/nonremovable, volatile/nonvolatile disk storage, magnetic diskdrive, floppy disk drive, tape drive, Jaz drive, Zip drive, LS-100drive, flash memory card, memory stick, optical disk drive such as acompact disk ROM device (CD-ROM), CD recordable drive (CD-R Drive), CDrewritable drive (CD-RW Drive) or a digital versatile disk ROM drive(DVD-ROM). A removable or non-removable interface 335 can be used tofacilitate connection.

The computer system 301 further can include software to operate inenvironment 300, such as an operating system 311, system applications312, program modules 313 and program data 314, which are stored eitherin system memory 332 or on disk storage 336. Various operating systemsor combinations of operating systems can be used.

Input devices 322 can be used to enter commands or data, and can includea pointing device such as a mouse, trackball, stylus, touch pad,keyboard, microphone, joystick, game pad, satellite dish, scanner, TVtuner card, sound card, digital camera, digital video camera, webcamera, and the like, connected through interface ports 338. Interfaceports 338 can include a serial port, a parallel port, a game port, auniversal serial bus (USB), and a 1394 bus. The interface ports 338 canalso accommodate output devices 321. For example, a USB port may be usedto provide input to computer 301 and to output information from computer301 to an output device 321. Output adapter 339, such as video or soundcards, is provided to connect to some output devices such as monitors,speakers, and printers.

Computer 301 can operate in a networked environment with remotecomputers 324. The remote computers 324, shown with a memory storagedevice 325, can be a personal computer, a server, a router, a networkPC, a workstation, a microprocessor based appliance, a peer device orother common network node and the like, and typically includes many orall of the elements described relative to computer 301. Remote computers324 can be connected to computer 301 through a network interface 323 andcommunication connection 337. Network interface 323 can be communicationnetworks such as local-area networks (LAN) and wide area networks (WAN).LAN technologies include Fiber Distributed Data Interface (FDDI), CopperDistributed Data Interface (CDDI), Ethernet/IEEE 1202.3, Token Ring/IEEE1202.5 and the like. WAN technologies include, but are not limited to,point-to-point links, circuit switching networks like IntegratedServices Digital Networks (ISDN) and variations thereon, packetswitching networks, and Digital Subscriber Lines (DSL).

FIG. 14 is a schematic block diagram of a sample computing environment40 with which the present invention can interact. The system 440includes a plurality of client systems 441. The system 440 also includesa plurality of servers 443. The servers 443 can be used to employ thepresent invention. The system 440 includes a communication network 445to facilitate communications between the clients 441 and the servers443. Client data storage 442, connected to client system 441, can storeinformation locally. Similarly, the server 443 can include server datastorages 444.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

1. A method for improving the operation of a workpiece stocker, thestocker comprising a chamber for storing a plurality of workpieces, thechamber being compartmentalized into a plurality of compartments; arobotic mechanism to transfer the workpieces from the chamber to an IOstation; and a plurality of emergency access ports for accessing theworkpieces in the event of the robotic failure, the method comprisingassessing that the robotic mechanism fails; and emergency accessing acompartment without contaminating other compartments.
 2. A method as inclaim 1 wherein the robotic failure is detected through a sensormechanism.
 3. A method as in claim 1 further comprising sealing allcompartments individually after determining the robotic failure.
 4. Amethod as in claim 1 wherein one compartment is unsealed for emergencyaccess while other compartments remain sealed.
 5. A method as in claim 1further comprising installing a load lock for the emergency access portof the unseal compartment before unsealing the compartment.
 6. A methodas in claim 1 further comprising installing a portable workpiece removalequipment connecting to the emergency access port of the unsealcompartment.
 7. A method as in claim 1 further comprising installing aload lock for the emergency access port of the unseal compartment beforeunsealing the compartment; and installing a portable workpiece removalequipment connecting to the emergency access port of the unsealcompartment.
 8. A method for improving the operation of a workpiecestocker, the stocker comprising a chamber for storing a plurality ofworkpieces, the chamber being compartmentalized into a plurality ofsealed compartments; a robotic mechanism to transfer the workpieces fromthe chamber to an IO station; and a plurality of emergency access portsfor accessing the workpieces in the event of the robotic failure, themethod comprising determining the current compartment having theworkpiece to be accessed; unsealing the current compartment;transferring the workpiece within the current compartment; andre-sealing the current compartment, wherein the workpieces are preventedfrom contamination by being sealed within the compartments when thechamber is exposed to the outside ambient during an emergency access. 9.A method as in claim 8 further comprising determining the nextcompartments to be needed after the current compartment; unsealing thenext compartments.
 10. A method as in claim 9 wherein the determiningthe next compartment determines at least one compartment to be neededafter the current compartment.
 11. A method as in claim 8 wherein theworkpiece stocker comprises a controller for determining the individualcompartments needed to be unsealed.
 12. A method as in claim 8 whereinthe robotic failure is detected through a sensor mechanism.
 13. A methodas in claim 8 further comprising sealing all compartments afterdetermining the robotic failure.
 14. A method for improving theoperation of a workpiece stocker, the stocker comprising a chamber forstoring a plurality of workpieces; a robotic mechanism to transfer theworkpieces from the chamber to an IO station; and an emergency accessport for accessing the workpieces in the event of the robotic failure,the emergency access port comprising a mating interface to a portableworkpiece removal equipment, the method comprising mating the emergencyaccess port to a portable workpiece removal equipment; removing theworkpieces without exposing the workpieces to outside ambient.
 15. Amethod as in claim 14 further comprising installing a portable cleanroom for mating with the mating interface.
 16. A method as in claim 14further comprising installing a load lock for the emergency accessports.
 17. A method as in claim 14 wherein the emergency access port isaccessed by an operator.